In the industry, molybdenum trioxide is prepared by roasting ammonium molybdate, or high-purity molybdenum trioxide is prepared by leaching molybdenum concentrate by oxygenating with acids and bases at high pressure by virtue of a chemical method, separating the impurities to prepare molybdate, and decomposing molybdate. With the continuous development of material science and application technologies, the problems of molybdenum trioxide prepared with the above method, such as coarse particles, agglomeration and low purity of molybdenum trioxide, could not be solved well. High-activity molybdenum trioxide is applied to the field of catalysts, which not only has specific requirements for impurities and particle size distribution of molybdenum trioxide, but also has specific requirements for reaction characteristics of molybdenum trioxide in solutions.
U.S. Pat. No. 4,551,313 discloses a rapid sublimation method of molybdenum trioxide having slag inclusion compositions (silicon, aluminum and heavy metal), which only solves the separation problem of molybdenum trioxide from impurities and improves the purities of molybdenum trioxide; and the particle size of molybdenum trioxide is above a micron size.
U.S. Pat. No. 6,468,497 discloses a production method of nano molybdenum trioxide, with the core of quenching molybdenum trioxide with liquid nitrogen (48° C.) and obtaining nano stripe-shaped molybdenum trioxide with a length of about 80-90 nm and a diameter of about 20-30 nm.
With the above methods, nano molybdenum trioxide could be prepared apparently, but the following problems exist: the production cost is high, the product is difficult to achieve the large-scale industrial application and promotion, and in addition, the product is in a shape of a needle, but in a special industry, such as a specific wear-resistant agent in high-level lubricating oil, the nano molybdenum trioxide is required to be spherical. Therefore, it is especially important to design an automatic, continuous, safe and reliable device and method of nano molybdenum trioxide having low equipment investment, simple process operation and low product cost.